Typewriter with multiple ribbons



' Feb. 6,1968 C.H.BERILL 3,367,471

TYPEWRITER WITH MULTIPLE RIBBONS Original Filed Dec. 12, 1960 4 Sheets-Sheet 2 INVENTOR.

M XX Q7 MM BY NM M A TTOENE K? Feb. 6, 1968 i c. H. BERILL 3,367,471 I 'I'YPEWRITER WITH MULTIPLE RIBBONS 4 Sheets-Sheet Original Filed Dec. 12, 1960 U INVENTOR. W K. Q) BY A TTOENEYS Feb. 6, 1968 c. H. BERILL TYPEWRITER WITH MULTIPLE RIBBONS 4 Sheets-Sheet 4 Original Filed Dec. 12; 1960 IN VEN TOR.

ATTOENEYS United States Patent M 3,367,471 TYPEWRITER WITH MULTIPLE RIBBONS Carroll H. Berill, 230 E. 51st St., New York, NY. 10022 Continuation of application Ser. No. 75,254, Dec. 12, 1960. This application Aug. 31, 1965, Ser. No. 484,058 20 Claims. (Cl. 197153) This application is a continuation of my application Ser. No. 75,254 filed Dec. 12, 1960, now abandoned.

This invention relates to attachments for typewriters and with which a plurality of ribbon copies can be made on the typewriter. The invention provides a device for operating the ribbons between different sheets of paper in the typewriter so that a type block striking the front ribbon will make an impression on the first sheet of paper and on all of the subsequent sheets of paper which also have ribbons in front of them. The attachment can be applied to a conventional typewriter without modifying the structure of the typewriter in any way.

It is an object of the invention to provide an improved attachment for making multiple ribbon copies on a typewriter. One problem has been the difiiculty in keeping the ribbons tight so that they are not carried above or below the line of typing when the paper is moved upward or downward by the rotation of the platen, and so that they do not smear the paper; and another difficulty has been the inconvenience of placing new paper in the typewriter and properly locating the different ribbons between the successive layers of paper.

It is another object of this invention to provide an improved feed mechanism for the ribbons. The invention has simple and rugged mechanism that automatically reverses the ribbons as they approach the end of their length.

Another object of this invention is to provide improved means for locking the unwinding ends of the ribbons and simultaneously tensioning the ribbons to hold them at the typing level whenever the platen is turned for a new line of typing, and when removing the paper from the typewriter. The invention maintains the ribbons under tension and locked while the platen is being moved to a new level for typing and to put new paper into the typewriter but the ribbon guides can be moved while the ribbons are thus locked, to withdraw all of the ribbons from the vicinity of the platen so that they are not in the way when new paper is being inserted into the typewriter, and in such a way as to maintain the tension of the ribbons.

In accordance with an important feature of the invention, each ribbon can be brought into position independently of the other ribbons and this provides a very convenient way of locating the successive ribbons in front of the successive sheets of paper on the platen and makes the reloading of the typewriter quick and convenient.

Another object of the invention is to provide improved automatic means for releasing the ribbons from their locked conditions and for again feeding the ribbons as soon as the typewriter goes back into service for typing on the new sheets. This release is obtained by the first operation of a key of the typewriter as typing is resumed.

Some features of the invention relate to constructions which make the apparatus more convenient to assemble, with resulting reduction in the cost of the attachment.

Other objects, features and advantages of the invention will appear or be pointed out as the description proceeds.

In the drawing, forming a part hereof, in which like reference characters indicate corresponding parts in all the views:

FIGURE 1 is a front view, partly broken away, showing the typewriter attachment of this invention;

FIGURE 2 is an end view of a portion of a typewriter and showing one of the control switches of this invention;

3,367,471 Patented Feb. 6, 1968 FIGURE 3 is a diagrammatic, perspective view showing the structure for operating the switch illustrated in FIGURE 2;

FIGURE 4 is an enlarged end view of the typewriter attachment shown in FIGURE 1 and showing the manner in which it is attached to a typewriter, and showing also another control switch for the invention;

FIGURE 5 is an enlarged, fragmentary, diagrammatic view, partly in section, illustrating the ribbon guides and the way in which they are supported for pivotal movement;

FIGURE 6 is a greatly enlarged sectional view taken on the line 6-6 of FIGURE 1;

FIGURE 7 is a fragmentary view of two successive ribbon guides with oppositely extending slots for receiving the guide-retaining latch;

FIGURE 8 is a fragmentary view, partly in section, showing the'guide-retaining latch and the manually operated handle for actuating the latch to release the ribbon guides successively;

FIGURE 9 is a greatly enlarged top view, mostly in section, showing the mechanism for driving the ribbon spools;

FIGURE 10 is a diagrammatic end view illustrating the manner in which the ribbon guides swing upwardly independently of one another for withdrawing the ribbons from the vicinity of the platen;

FIGURE 11 is a diagrammatic view of a solenoidoperated switch for locking and unlocking the ribbon feed, and for supplying additional paths for the flow of current to the actuator;

FIGURE 12 is a diagrammatic, perspective view showing the mechanism for locking the ribbon feed;

FIGURE 13 is an enlarged sectional view through the solenoid-operated switch of FIGURE 11;

FIGURE 14 is a greatly enlarged, fragmentary view of the mechanism for reversing the ribbon feed;

FIGURE 15 is a sectional view, on a reduced scale, on the line 1515 of FIGURE 9;

FIGURE 16 is a diagrammatic view, on a reduced scale, showing the operation of the reversing mechanism illustrated in FIGURE 14;

FIGURE 17 is an enlarged, fragmentary, perspective view of the teeth of the actuator shown in FIGURE 9; and

FIGURE 18 is a wiring diagram for the apparatus shown in the other figures.

The invention includes a frame or housing 20 which is made up of a center housing 22 and two end housings 23 and 24. The center housing and the end housings are rigidly connected together to form a unitary structure. An arm 26 extends downwardly from the end housing 23 and a corresponding arm 27 extends downwardly from the end housing 24. These arms 26 and 27 are connected to the housings 23 and 24, respectively, by bolts 29.

The arm 27 is connected to the housing 24 with some adjustment for fitting the attachment to different typewriter models. The lower bolt 29 (FIGURE 4) provides a pivotal connection between the arm 27 and the housing 24 and the upper bolt 29 extends through a slot 30 having its center of curvature at the axis of the lower bolt 29. When the bolts 29 are loosened, the arm 27 can be adjusted angularly about the lower bolt 29; and when these bolts 29 are tightened, the arm 27 is rigidly connected to the housing. The arm 26 at the other end of the typewriter has similar pivotal adjustment.

At the lower end of the right hand arm 27, there is a slot 32 which is wide enough to receive the shaft 34 by which the platen 36 of the typewriter is carried. There is a latch 38 attached to the arm 27 by a pivot connection 40.

This latch is held, in the position shown, by a spring 42. One end of the spring 42 is anchored to a portion of the latch 38 below the pivot 40; and the other end of the spring 42 is anchored to the arm 27. When the platen is to be removed from the typewriter, the latch 38 1s rocked clockwise about the pivot 40 to clear the top of the slot 32 and the shaft 34 can then be raised out of the slot 32. This feature permits the platen to be removed while the attachment of this invention remains undisturbed on the typewriter.

There is a channel 46 at the bottom of the frame or housing 20, and forming an integral part thereof. Tl'llS channel 46 rests on a carriage frame 48 of the typewriter to which the attachment is to be connected. Clips 50 are secured to the channel 46 by fastening means 52 and these clips 50 hook under -a portion of the frame 48 to secure the attachment to the typewriter carriage.

Lugs 54 extend forwardly from the frame or housing 20; and there is a shaft 56 extending through these lugs. This shaft 56 serves as an axle for a bail 58 havlng rollers 60 for holding the paper against the platen 36 1n the usual manner. The shaft 56 also provides a pivot for hinge connections between the frame or housing 20 and a group of ribbon guides. This group includes four ribbon guides 61, 62, 63 and 64. The upper ribbon gulde 61 Will be described in detail. The other ribbon guldes 62-64, which lie beneath the top guide 61, are of similar construction but with certain modifications which will be explained.

The ribbon guide 61 has downw-ardly-extendlng arms 67 and 68 (FIGURE 1). These arms are connected together at their upper ends by a middle portion 69 of the ribbon guide. In the preferred construction, all parts of the ribbon guide are of one-piece construction and it is a feature of the ribbon guide that it can be made as a single stamping. The middle portion 69 has lugs 70, at spaced regions along its length, extending around the shaft 56, and forming a hinge connection for the ribbon guide to the frame or housing 20. In the space between successive lugs 70 there are similar lugs 70' which extend from the other ribbon guides 62-64 so that all of the ribbon guides are hinged to the frame or housing 20 by the same shaft 56. This makes all of the ribbon guides hinge about a common axis, and the ribbons are held down by the extending end of the shaft 56 so that they all bend about substantially the same axis as shown in FIG- URE 10.

At the lower part of the arm 67, the ribbon guide has a depressed portion where the arm is wider and this depressed portion provides a channel 72, in which the ribbon runs. The ribbon is omitted in the left-hand portion of FIGURE 1 in order to show the channel 72. There is a slot 74 through the bottom of the channel 72 and at an angle of 45 to the length of the channel. A ribbon passing lengthwise within the channel 72 extends through the slot 74 and then in a direction parallel to the platen 36 along the full length of the platen to the arm 68 at the other end of the ribbon guide.

Toward the right-hand end of the platen 36 there are four ribbons shown extending toward the arms at the right-hand ends of the ribbon guides. The upper ribbon 76 extends through a slot 74 in the right-hand arm 68 of the upper ribbon guide 61; and this ribbon extends along a channel in the arm 68 and upwardly to a ribbon spool 77 about which the ribbons wind.

All of the ribbons wind on the same spool 77. There is a corresponding spool at the other end of the typewriter attachment; but this spool is omitted in FIGURE 1 of the drawing in order to show a spool holder 7 8 having an .axle and pins for receiving the ribbon spool and for rotating it. As in the case of the right-hand spool 77, all of the ribbons wrap on the same spool at the left-hand end of the attachment. The left-hand spool 77 is shown in FIGURE 9. The ribbons unwind from one spool and wind on the other, and then reverse, to obtain movement of the ribbons relative to the movement of the carriage 48 past the typing station in accordance with conventional practice.

FIGURE 6 shows a sectional view through the different ribbon guides 61, 62, 63 and 64. This figure shows the channel 72 along which the ribbon 76 runs. The purpose of the channel 72 is to impart a necessary rigidity to the ribbon guide which is otherwise made very thin in order to have the ribbons close together and to avoid different lengths of ribbon path when the ribbons are swung outwardly and upwardly away from the platen. In FIGURE 6 the thickness of the ribbons and ribbon guides is greatly exaggerated in order to be able to show the construction more clearly in section.

Each of the successive ribbon guides 61-64 is slightly wider than the one above it so that the ribbon guide immediately above can fit into the channel of the ribbon guide below. This provides a nesting which brings the ribbon guides closer together while still permitting each guide to have a flange 80 forming one side of its channel.

The ribbon guides 61-64 swing about the axis of the shaft 56, as previously explained; and each ribbon guide can swing independently as shown in FIG- URE 10. In the operation of the invention, however, the ribbon guides 61-64 are preferably withdrawn from the platen at the same time so as to permit typed copies of paper with typing on them to be removed from the typewriter and new paper inserted. The lowermost sheet of paper is then held against the platen, with the other sheets sloping away from the platen, and the lowermost ribbon guide 64 is brought back into position to locate its ribbon 76 in front of the rearmost sheet of paper.

The next-to-last sheet of paper is then pushed back toward the platen and over the lowermost ribbon, and the next ribbon guide 63 is brought down into position to locate its ribbon in front of the new sheet of paper. In like manner, each successive sheet of paper is moved into position over the next underlying ribbon, and the next ribbon guide is brought down. While the invention is illustrated with four ribbons, it will be understood that it can be made with more or fewer ribbons.

All of the ribbon guides are conveniently lifted simultaneously away from the platen by a handle 84 (FIG- URE 1) extending from the lowermost ribbon guide 64. This handle 84 is preferably of one-piece construction with the ribbon guide 64 and a part of the same stamping. Although handles can be provided for the other ribbon guides, there are no such handles in the preferred construction because they are not necessary.

The ribbon guides are retained in their raised positions by a latch. There is a longitudinal slot 86 in the righthand arm of each of the ribbon guides 61-64. These slots are shown in FIGURE 6; and two of them are shown in plan view in FIGURE 7 where the ribbon guides have been shifted transversely to better illustrate the slots 86. Actually, the ribbon guides never occupy the relative positions shown in FIGURE 7.

There is a fin 88 (FIGURE 4) extending from the front of the housing 24. This fin is of arcuate shape to compensate for the angular movement of the ribbon guides. The fin 88 extends through the slots 86.

A latch 90 is located in a slot 92 in the fin 88. This latch 90 is best shown in FIGURE 8. It extends through transverse slots 94 in the ribbon guides. The slot 94, in each successive ribbon guide 61-64, is located mostly on a different side of the longitudinal slot '86 in the ribbon guide. This staggered relation of the transverse slots 94 is clearly shown in FIGURE 6.

Referring again to FIGURE 8, the latch 90 is at the lower end of a stem 98 supported on a pivot connection 100. There is a tail 102 extending upwardly from the stem 90 into a slot 104 above the pivot 100. The ends of this slot provide limit stops for restraining the swinging movement of the latch 90 about the pivot 100.

The latch 90 is operated by a manually actuated handle 106 attached to the housing 24 by the pivot 100. This handle 106 carries a spring 108 which engages a crank 110 extending from one side of the latch stem 98.

This spring 108 fits into a socket in the end of the crank 110. When the handle 106 is moved into the position shown in dotted lines in FIGURE 8, the spring 108 is flexed and shifted beyond a center line with the pivot 100 so that the spring 108 rocks the stem 98 and latch 90 counterclockwise until the tail 102 strikes against the left-hand end of the slot 104. Movement of the handle 106 back to the full-line position shown in FIGURE 8, when the latch 90 is shifted into its left-hand position, causes the spring 108 to be flexed and shifted beyond a center line with the pivot 100 so that the force of the spring snaps the stem 98 and latch 90 clockwise about the pivot 100 and into the full-line position shown in FIGURE '8.

Comparing the different positions of the latch 90, as described in connection with FIGURE 8, with the staggered transverse slots 94 shown in FIGURE 6, it will be apparent that the ribbon guide 64 is released by the retaining means when the latch 90 moves to the right. It will also be apparent that the ribbon guide 63 can not move downwardly until the latch '91) is moved to the left. Similarly, movement of the latch back to the right is necessary to release the ribbon guide 62; and movement back to the left is required to release the top ribbon guide 61. Thus, oscillating movement of the handle 106 (FIGURE 8) causes successive release of the ribbon guides from the retaining means which hold them in elevated positions.

Since the ribbon guides 61-64 are not in vertical positions when retained in their raised locations by the latch '90, they will fall by gravity when released; but in the preferred construction springs are provided for urging the ribbon guides downwardly into positions adjacent to the platen, and for holding the ribbon guides down. One of these springs is shown in FIGURE and it will be understood that there are similar springs for the other ribbon guides.

FIGURE 5 shows a lug 114 attached to the ribbon guide 61 and surrounding the shaft 56. This lug 114 is the same as the lugs 70 except that the opening through it is substantially larger in diameter than the shaft 56 so that a coil spring 116 can be placed within the lug 114 and around the outside of the shaft 56. This coil spring is anchored at its left-hand end to the lug 114. The righthand end of the spring 116 extends past the end of the lug 114 and is anchored to a portion of the frame 20. The spring is twisted in a direction to cause it to urge the ribbon guide to swing downwardly toward the platen 36.

FIGURE 2 shows one of the electric switches by which the operation of the ribbon feed is controlled. All of the typewriter parts shown in FIGURE 2 are conventional except for the switch. This switch 120, which controls locking and tensioning of the ribbons is attached to the typewriter frame 48 by a clip 122. The switch includes an upper contact 124 and a lower contact 126. There is a double-faced movable contact 128 on a switch arm 130-. A cam 132 made of electric insulating material is connected to the arm 1311' and this cam is displaced by a crank 134 which rocks about an axis of a shaft 136 (FIGURE 3) extending through the back of the housing of the switch 120.

Referring again to FIGURE 2, the lower contact 126 is fixed to the housing of the switch 120. The upper contact 124 is relatively fixed but is connected to the housing by a resilient arm 133 which can yield as necessary to provide for over-travel of the cam 132. The arms 130 and 138 are insulated from one another but are connected to the housing of the switch by insulating blocks 140. Conductors 142 lead from the different contacts through a cable 144. The switch arm 136 is a spring and holds the contact 128 against the fixed contact 126 when the cam 132 is not displaced by the arm 134.

The platen 36 of the typewriter is operated, to space successive lines of typing, by a handle 146 or by manually 6 turning the knobs 147 (FIGURE 1) on the ends of the platen shaft. The handle 14-6 operates a pawl to rotate a ratchet 152 (FIGURE 3). This mechanism is found on all conventional typewriters and no illustration of it is necessary for a complete understanding of this invention.

In order to insure that the platen will always have the same angular movement, a roller 150 is provided for moving the ratchet 152 forward, or backing it if necessary, to center the space between ratchet teeth under this roller 150. When the typewriter is set for single spacing, the ratchet 152 is moved by the handle 146 for a distance of one tooth, but when the typewriter is adjusted for double and triple spacing, the operation of the handle 146 (FIGURE 2) moves the ratchet 152 for a distance of two or three teeth. Typewriters also have a lever for disengaging the roller 150 from the ratchet 152 when it is desired to stop the platen between lines.

The roller 150 is carried by a lever 153 and is held against the ratchet by a spring 154. The roller 150, lever 153 and spring 154 are conventional typewriter structure. It is a feature of the invention, however, that the switch is operated by this conventional lever 153 of the type writer. The shaft 136 turns in a bearing 156 in the hous ing of the switch 120, and on a part of a switch housing that extends under the portion of the typewriter frame on which the clip 122 hooks. There is a crank 158, at one end of the shaft 136, in position to be rocked clockwise in FIGURE 3 when the lever 153 is moved by. a ratchet tooth passing the roller as the platen is rotated upwardly or downwardly. The rocking movement imparted to the shaft 136 moves the crank 134 in a direction to displace the cam 132 and to thereby lift the switch arm 130.

In FIGURE 3, the view of the switch 120 is taken from the opposite side of the switch as compared with FIGURE 2. The rocking movement of the crank 134, with each turn of the platen, moves the crank 134 counterclockwise, as viewed in FIGURE 2, and this displaces the cam 132 upwardly to bring the contact 128 against the upper contact 124, and to break the circuit between the contacts 126 and 128.

FIGURE 4 shows another switch 160 of the control circuit for the attachment. This switch 169, which controls the ribbon feeding and unlocking, has conductors and contacts corresponding to those of the switch 126 and designated by the same reference character, with a prime appended. A movable contact 128' is normally held against a fixed contact 126' by the pressure of a switch arm 130 by which the contact 128 is carried. The arm 130' is moved, to bring the contact 128' against the other fixed contact 124 by an actuator lever 162 that extends beyond the housing of the switch 160. This actuator lever 162 has a spring bias toward the position shown in fuil lines in FIGURE 4. The switch 160 has conductors 142.

This actuator lever 162 co-operates with a carriage escapement control bar 164 of the typewriter. This control bar 164 is not a part of the attachment of this invention. Any conventional typewriter has such a control bar 164 supported by links 166 and actuated by another link 168 whenever a key of the typewrite is operated. The typewriter has keys, each of which operates a type block for one of the letters or symbols through conventional motion transmitting linkage 168a shown diagrammatically in FIGURE 1. A conventional typewriter of this type is illustrated in the Gates Patent 2,869,704. The switch 160 is attached to the frame of the typewriter by any suitable fastening means and the lever 162 is bent as necessary into the position required to locate it in front of the control bar 164. In its broader aspects, the lever 162 is representative of motion-transmitting connections.

When a key is struck, the control bar 164 is moved forward, and the type block of that key strikes the ribbon in front of the paper on the platen to print the letter on the paper. As the type block moves back away from the platen, and the key returns to its original position, the carriage escapement control bar 164 moves rearwardly and it is during this rearward movement that the carriage shifts the platen axially in preparation for the printing of the next letter. The spring bias of the lever 162 moves it from the dotted-line position back to its full-line position.

Since the switch 160 controls the feeding of the ribbons, it is important to operate it So as to prevent the ribbon from moving while the type block is striking the forward ribbon. There is a ratchet means comprising a pawl 169 pivotally connected to the lower end of the lever 162 and so arranged that it swings freely into position to pass an actuator on cam block 170 on the switch arm 130' when the lever 162 is rocked by forward movement of the control bar 164; but when the lever 162 moves back toward its original position, the pawl 169 displaces the cam block 170 to cause a momentary contact of the contact 128' with the contact 124'. As the lever 162 completes its movement back to its full-line position, the pawl 169 moves beyond the cam block 170 and the switch arm 130 returns the contact 128 to its original position, touching the fixed contact 126.

The operation of the switch 169, with every actuation of the typewriter, supplies impulses of powe to an electric actuator or motor located in the housing 23 (FIG- URE 1). This actuator rotates the spool holder 78 when the ribbons are being wound in one direction, and rotates the spool 77 at the other end of the attachment when the ribbons are being operated in the other direction. There are motion-transmitting connections between the actuator and the ribbon spool holders as shown in FIG- URE 9.

The actuator includes a magnetic coil 172 secured to the housing 23. Within this coil, and also secured to the housing 23, there is a cup 174 with teeth 176. The actuator has a disc 178, attached to a plunger 179, that extends into the space surrounded by the coil 172. The cup 174, disc 178 and plunger 179 are made of ferrous metal. A sleeve 180 surrounds and is attached to the plunger 179, and there are teeth 182 on the sleeve 180 complementary to the teeth 176 of the fixed cup 174.

FIGURE 17 shows the correlation of the teeth 176 with the teeth 182. Each group of teeth has one side which is parallel to the axis of the cup 174 and the sleeve 180. The other side of each tooth slopes at an angle, as illustrated.

When the sleeve 180 moves axially, that is, downwardly in FIGURE 17, the sloping surfaces of the fixed teeth 176 thrust the teeth 182 toward the right in FIG- URE l7, and thus a rotary movement is imparted to the sleeve 180. As the sleeve moves back, that is upwardly in FIGURE 17, the teeth return to the positions shown in FIGURE 17 and this entails rotary movement in the opposite direction.

Referring again to FIGURE 9, energizing of the coil 172 causes the disc 178 and the plunger 179 to be attracted by the coil and to move toward the right with resulting rotational movement imparted by the teeth 176 and 182, as already explained. This movement twists a helical spring 184 which is connected at one end to the disc 17-3 and connected at the other end to the fixed cup 174. Whenever the supply of current to the coil 172 is interrupted, the spring 184 returns the disc 178 and sleeve 180 to their original position.

A shaft 186 extends axially through openings in the cup 174, the disc 178 and the plunger 179. A key 188 is attached to the shaft 186 by a pin 189 and this key extends from both sides of the shaft 186 and fits into a slot 198 in the disc 178. This operative connection between the disc 178 and the shaft 186 permits the disc 178 and the plunger 179 to move axially with respect to the shaft 186, but all rotational movement of the disc 173 and plunger 179 is imparted to the shaft 186 with only as much lost motion as results from having the key 188 fit with a running fit into the slot 191 The slot 190 is of limited length so as to limit the movement of the disc 178 away from the coil 172 under influence of the spring 184. This movement is limited so as to prevent the teeth 176 and 182 from moving out of engagement with one another.

With this construction, it will be apparent that successive closings of the circuit of the coil 132 cause the disc 178 and plunger 179 to move toward and from the cup 174- with resulting oscillation of the shaft 136. The degree of oscillation, and the amount of rotary motion imparted to the spool holder with each stroke of the actuator can be changed by changing the stroke of the disc 178 and the plunger 179. This can be done by an adjusting screw 191 threaded through a part of the housing 23.

This oscillation of the shaft 186 is converted into rotary motion by a clutch 194 near one end of the shaft. This clutch 194 includes a spool 196 secured to the shaft 186 and a spring 198 wrapped around the spool. The spool 196 and the spring 198 are within a hub of a gear 200 which rotates on an extension of the shaft 186. The spring 198 has one end secured to the gear 206 and the spring is wrapped on the spool 196 in a direction to tighten the spring on the spool when the shaft 186 rotates in the direction in which it turns when the disc 178 and plunger 179 move toward the cup 174. The friction of the spring 198 against the spool 196 causes the spring to wrap tighter on the spool and firmly grip the spool when it turns in one direction, but when the spool rotates in the opposite direction, this friction tends to loosen the grip of the spring on the spool so that the spool turns without turning the spring.

When the spring wraps tighter on the spool 196 and turns with the spool, the spring rotates the gear 200.

Upon return movement of the disc 178 and plunger 179, away from the cup 174, the spring 198 unwinds to release its grip on the spool 196, and thus no reverse drive is imparted to the gear 201). In order to prevent reverse movement of the gear 200 as a result of some friction drag, there is another spring 204 wrapped around the outside of the hub of the gear 200 and in a direction to tighten when the gear 200 starts a reverse movement. This spring 204 has one end secured to the fixed housing 23 and acts as a holding pawl of a ratchet to prevent reverse movement of the gear 200.

The gear 208 meshes with an idler gear 212 secured to a shaft 214 that rotates in bearings 216, in the housing 23. The idler gear 212 is much wider than the gear 200 and meshes with another gear 218 attached to the spool holder 78. In the construction illustrated, the spool holder 78 turns on the extension of the shaft 186 as a bearing. and in a bearing in the housing 23. A spring 219 within a hub of the gear 218 has one end anchored to the housing 23 and this spring tightens to exert some braking effect when the spool holder is turning in a direction to unwind the ribbon. This prevents coasting of the spool holder and makes possible tensioning of the ribbons by a single impulse to the actuator when the ribbon spool is locked. The spring 219 loosens and exerts no braking effect when the spool holder turns in a direction to wind the ribbons.

The shaft 214 is axially movable. When it is in the position shown in FIGURE 9, the idler gear 212 meshes with both of the gears 200 and 218. When the shaft 214 is shifted toward the left in FIGURE 9, the idler gear 212 moves into the dotted-line position in which it continues to mesh with the gear 260 but no longer meshes with the gear 218. Thus, with the idler gear 212 in its full-line position, the rotation of the gear 200 rotates the ribbon spool holder 78; but with the gear 212 shifted to the left into the dotted-line position, rotation of the gear 200 still rotates the shaft 214 but no longer operates the ribbon spool holder 78.

The ribbon spool 77, at the other end of the attachment, is rotated by a ribbon spool holder which is of similar construction to the ribbon spool holder 78, and which is driven by a gear 222. This gear 222 meshes with a gear 223, secured to the shaft 214, when the shaft 214 is shifted toward the left so as to take the idler gear 12 out of mesh with the gear 218. Thus, when the actuator gear 288 is driving the gear 218 to rotate the ribbon spool holder 78, no power is transmitted to the holder for the spool 77; and conversely, when the shaft 214 is in position to transmit motion from the gear 200 to the gear 222 of the holder for the spool 77, no power is transmitted to the spool holder 78. The gears 212 and 223 are, therefore, motion-transmitting connections for operating the driving means for the spool holders.

The shaft 214 is operated automatically to move it axially whenever one of the ribbon spools becomes unwound. The construction for obtaining this result is shown in FIGURE 9. A spool 77' on the spool holder 78, has a hub with a key 230 located in a keyway in the hub and which projects beyond the end of this spool 77'. The key 238 is urged radially outward by a spring 232, but the key is held down in the keyway in the spool hub by the ribbons 76 which are wrapped on the spool.

When the last convolution of the ribbons on the spool 77 starts to unwind, the ribbons no longer hold the key 230 down in its keyway.

There is a thin cam plate 236 on the spool holder 78 and this c-am plate has a notch 238 (FIGURE 15) in its bearing surface which turns on the hub of the spool holder 78 for the spool 77'.

After the key 230 is no longer held in its keyway by the ribbons on the spool, the key is free to move radially outward the next time it comes into radial alignment with the notch 238.

This notch 238 slopes gradually away from the hub of the spool holder 78 and then has a shoulder 240, against which the key 230 abuts. Further rotary movement of the spool holder 78 causes the key 230 to force the cam plate 236 to turn clockwise in FIGURE 15. A spring hook 244 fits into the cam plate 236 at its lower end where the lower end of the hook 244 is integrally connected to the cam plate 236. The other end of the spring hook 244 engages a lever 248. This lever 248 has an upand-down movement, as will be explained in connection with FIGURES 14 and 16. For the present, it is sufiicient to understand that when the ribbons are unwinding, the lever 248 is in its elevated position, shown in FIGURE 15. Clockwise movement of the cam plate 236 forces the spring hook 244 to first bend and then rock clockwise with the cam plate 236, and to force the lever 248 downwardly. This reverses the direction of the ribbon drive, as will be explained in connection with FIGURES 14 and 16.

Referring to FIGURE 14, the lever 248 is supported at its center on a fulcrum bearing 252 at a fixed location on the frame 20. There are hooks 254 attached to the lever 248 at locations spaced to either side of the fulcrum bearing 252. These hooks limit the extent to which either arm of the lever 248 can move downwardly. The hooks 254 extend through openings in the top of the frame 28 and their upper ends are too large to come through the openings. Thus contact of the upper ends of the hooks 254 with the top of the frame 28 stops down- Ward movement of either end of the lever 248.

FIGURE 16 illustrates the operation of the lever 248. It is shown in full lines at its limit of counter-clockwise movement, and in dot-and-dash lines at its limit of clockwise movement. There is a helical cam 258 on the face of each of the gears 212 and 223 which confronts the other gear. These earns 2.58 rotate as units with their gears 212 and 223.

When the lever 248 is in the full-line position shown in FIGURE 16, its left-hand end is in the path of the cam 258 which is attached to the gear 212. Rotation of the gear 212, therefore, causes its cam 258 to thrust against the end of the lever 248. As the cam rotates, it thrusts itself, its gear 212 and the shaft 214 toward the left since the lever 248 can not be moved in the direction 11) of its length. This shifts the gear 212 into the dotted-line position shown, to disengage it from the spool holder gear 218, as already described in connection with FIGURE 9.

Referring again to FIGURE 16, this axial movement of the shaft 214 moves the gear 223, and its cam 258, into the dotted-line positions shown; but the cam 258 does not contact with the right-hand end of the lever 248 be cause the end of the lever is beyond the circumference of the cam.

When the lever 248 is pulled downwardly into its dotand-dash line position, its right-hand end is moved into the path of the helical cam 258 of the gear 223, and this causes the shaft 214 to be shifted toward the right again to reverse the direction of ribbon drive. The phase angle of each of the cams 258 about the axis of the shaft 214 is correlated with the cam 236 (FIGURE 15) and its notch 238 so that the lever 248 is shifted into the paths of the cams 258 at angular positions of the shaft 214 which locate the low portions of the cams 258 in front of the ends of the lever 248.

Referring again to FIGURE 14, the ribbon feed can be reversed manually by pushing down on one or the other of the hooks 254 and by moving the shaft 214 axially by means of a knob 262 at the end of the shaft 214 beyond the side wall of the housing 23.

In order to maintain a tension on the ribbons, so that they can not be displaced when the platen is turned to move the paper, means are provided for locking the unwinding ribbon spool holder while rotation is imparted to the winding spool holder. The unwinding holder is locked by pressing pawls 266 and 268 (FIGURE 12) into engagement between teeth of the gears 218 and 222, respectively.

Since the gears 218 and 222 always turn in opposite directions with respect to one another, one pawl 266 or 268 is effective to lock its adjacent gear 218 or 222 while the other pawl ratchets freely over the gear teeth. This feature makes it practical to engage both of the pawls 266 and 268 with the gears 218 and 222, respectively, whenever either gear is to be locked, and this simplifies the locking mechanism.

The pawl 266 is part of a lever 272 supported by a pivot 274 at a fixed location in the frame 20. A spring 276 extends from the lever 272 and is integrally connected to the lever 272 at one end. This spring 276 extends across a cam 278 secured to a cam shaft 280. An end portion 281 of the lever 272 extends under the cam 278 so that the cam can force the pawl 266 to withdraw from be tween the teeth of the gear 218 even though torque imparted to the gear 218 by the tension of the ribbons causes substantial friction between the pawl 266 and the teeth .of the gear 218. Rotation of the cam 278 causes the lever 272 to oscillate about its pivot connection 274 and to move the pawl 266 into and out of engagement between teeth of the gear 218.

The reason for using the spring 276, to transmit motion from the cam 278 to the pawl 266, is to obtain some resilience in the motion-transmitting connection so that the pawl can ratchet over the gear teeth when the gear 218 isrotating counter-clockwise in FIGURE 12. Another reason is to permit the cam 278 to turn even though the pawl 266 is not in line with a space between two teeth. In such a case, the spring 276 will bend and the spring will force the pawl into engagement between teeth of the gear 218 as soon as the gear has turned far enough to bring a space between teeth into line with the pawl 266.

The pawl 268 is part of a lever 284, the constnuction being similar to the pawl 266 and lever 272, and the lever 284 is similarly operated by a cam 278' secured to the cam shaft 280.

The cam shaft 280 has a crank 285 secured to it and axially spaced from the cams 278 and 278'. This crank 285 is operated by a solenoid-actuated linkage, shown in FIG- URE 11. The crank 285 has a sloping surface 286 located adjacent to the lower end of a link 288. This link 288 is supported by a pivot 29% on a fixed bracket 292 projecting from a solenoid housing 294.

The upper end of the link 288 has a flat end 298 and there. is a leaf spring 300 secured to the solenoid housing 294 at one end and bearing against the fiat end 298 of the link 288. Rocking movement of the link 288 about its fulcrum 290, in either direction, bends the spring 300. Thus the spring 300 serves to return the link 288, to the position shown in FIGURE 11, whenever the link 288 is displaced from that position.

FIGURE 13 shows the interior of the solenoid housing 294. There are two coils 304 and 306 in the housing 294. A ferrous metal plunger 310 slides in a sleeve 312 located within the coils 304 and 306. Energizing of the coil 304, when the coil 306 is not energized, causes the plunger 310 to be pulled toward the left in FIGURE 13. Energizing \f the coil 306, when the coil 304 is not energized, causes the plunger 310 to be moved towards the right.

The solenoid housing 294 is attached to a bracket 316 by screws 318 and 320, and this bracket is rigidly connected with the frame of the attachment. The plunger 310 is connected with a link 324.

Referring again to FIGURE 11, the right-hand end of the link 324 is connected with the link 288 by a pivot 326. When the link 324 is moved toward the right by a coil in the housing 294, the link 288 is rocked counter-clockwise about its pivot 296. When the link 324 is moved toward the left by a coil in the housing 294, the link 288 is rocked clockwise. It will be apparent from FIGURE 11 that counter-clockwise movement of the link 288 moves the lower end of the link 288 against the sloping surface 286 of the crank 285 and displaces the crank 285 in a direction to rock the cam shaft 80 in a clockwise direction.

Referring again to FIGURE 12, there is a lug 334 at the shaft end of the crank 285. Clockwise movement of the link 288 beyond its mid position causes the lower end of the link 288 to strike the lug 334 and to rock the cam shaft 280 back into a position that turns the cams 278 and 278 far enough to move both of the levers 272 and 284 down and to disengage the pawls 266 and 268 from the gears 218 and 222. Thus the solenoid in the housing 294, the crank 285 .and the shaft 288 constitute another actuator for operating the cam means 278 and 278' to retract the pawls 266 and 268 from engagement with the gears 218 and 222, respectively.

Referring again to FIGURE 11, the link 288 also serves to actuate another switch 340 which consists of two resilient arms 342 anchored at their left-hand ends to insulating blocks 344 and carrying contacts at their free ends. The lower arm 342 is operated by a cam 346 attached to a lever 348 which is rocked about a fixed pivot 350. This lever 348 is connected to the link 288 by a link 352. When the link 288 rocks in either direction from its mid position, it moves the lever 348 angularly far enough to close the switch 340. The resilience of the arms 342 holds the contacts of the switch 340 away from one another so that the switch is open when not moved into closed position by the cams 346. There are preferably two switches 340 located side-by-side and each having its operating cam 346 rocked by the lever 348.

FIGURE 19 is a wiring diagram for the apparatus shown in the other figures. Power is supplied to all of the switches 120, 160 and 340 from a power line 360.

Each operation of the typewriter by striking a letter key causes operation of the double throw switch 160. Operation of the switch 160 by return movement of the actuator lever 162 (FIGURE 4) moves the switch to cause momentary closing of the contacts 128' and 124' (FIGURE 18) and opening of the contacts 126' and 128'. Completion of the movement of the lever 162 leaves the switch 160 in its original position, shown in FIGURE 18, as previously explained in connection with FIGURE 4. The momentary closing of contacts 128' and 124 closes a circuit from the power line 360 (FIGURE 18) through the contacts 124' and 128, switch arm 130' and through conductors 362 and 363 to the coil 172 of the power actuator of the apparatus. The other end of the coil 1'72 is connected, by a conductor 364, with a conductor 366 constituting the ground connection of the circuit.

The successive impulses to the coil 172, with each operation of a key of the typewriter, cause successive angular movements of the spool holders first in one direction until the ribbons unwind from one spool, and then in the opposite direction, as already explained.

When power is supplied through the switch 160 to the conductors 362 and 363, it is also supplied through the switch to the coil 304, but this operation will be explained more fully after the description of the operation of the circuit for tensioning the ribbons.

Whenever the platen is rotated to move the paper, the switch 120 is operated to move the contact 128 away from the contact 126 and up against the contact 124. This closes a circuit from the power line 360 through a conductor 370, contact 124, and switch arm 130, to a conductor 372. From the conductor 372 there are two parallel circuits. One leads through the conductor 362 to switch arm 130', through contacts 128' and 126' and through a conductor 376 to the coil 306 which is grounded by a conductor 378 and the conductor 366.

The conductors 142 (FIG. 2) in the housing of the switch 120 are not so designated in FIG. 18 because of the small scale of FIG. 18; but it will be apparent from the switch contacts that conductors 3'70, 372 and 380 in FIG. 18 are the conductors which are led through the cable 144 in FIG. 2 to form the switch connecting condoctors 142 within the housing of the switch 128.

The energizing of the coil 306 locks the unwinding spool, as has been explained in connection with FIG- URES 1l-13. At the same time that electric power is supplied to the coil 306, it is also supplied to the coil 172 through the conductor 363. This energizing of the coil 172 causes the winding spool to turn while the unwinding spool is locked; and this tensions the ribbons.

The movement of the links 324 and 288 (FIGURE 11) to lock the unwinding spool, closes the switch 340. Referring again to FIGURE 18, the closing of the switch 340 establishes a circuit from the power line 360 to the conductor 362 in parallel with the circuit through the switch 120 so that ample power is supplied to the actuator coil 172 and the locking coil 306. The closing of this parallel circuit through the switch 340 supplies additional power to the actuator coil 172 because the resistance to current flow is greatly reduced by having the two circuits in parallel. Also, the time of current flow may be increased somewhat if the platen is being turned quickly because the switch 120 will close only momentarily as the platen is rotated rapidly, but the switch 340 remains closed for substantially the same length of time regardless of the speed with which the platen is turned.

The length of time that the switch 340 remains closed, after the switch 120 opens the contacts 124 and 128, depends upon inductive characteristics of the coils 304 and 306. These coils are wound, preferably with some ferrous metal in their magnetic circuits, so that energizing of either coil immediately builds up a strong magnetic field in that coil, but the field is contracted and reduced in strength by the induction which builds up in the unenergized coil 304 or 306. Even though a voltage is maintained on the coil 304 or 306, through the switch 340, the strength of the magnetic field of the energized coil with respect to its adjacent coil becomes sufficiently reduced so that the plunger 310 (FIGURE 13) is moved back into its mid position by the force of the spring 300 (FIGURE 11) hearing against the flat face 298 on the top of the link 288. This movement of the link 288 causes the switch 340 to open, as previously explained.

In practice, the switch 340 may not start to open until after the switch 120 has moved the contacts 124 and 128 apart; but the switch 340 opens sufficiently to break its circuit before the switch 120 has returned the movable 13 contact 128 to its original position against the contact 126.

Opening of the circuits through the switch 340 and through the contact 124 of the switch 120 cuts off the supply of power to the locking coil 306, but this does not unlock the ribbons. It will be evident from FIGURE 12 that after operation of the cams 278 and 278, to push the pawls 266 and 26 8 into engagement with teeth of the gears 218 and 222, the pawls will remain engaged and keep the ribbons locked unless the cams 278 and 278' are moved to unlock the pawls.

Reverse movement of the cams 278 and 278' to thrust the levers 272 and 284 downwardly, and to disengage the pawls 266 and 268 from the gears 218 and 222, respectively, requires energizing of the coil 304 (FIGURE 13). Such energizing of the coil 304 moves the plunger 310 to the left in FIGURE 13 and pulls the link 324 in a direction to rock the link 288 (FIGURE 11) clockwise so that the lower end of this link 288 strikes the lug 334 and turns the cam shaft 280 counter-clockwise, as previously explained.

Referring again to FIGURE 18, the unlocking coil 304 is energized each time the switch 160 is operated to close a circuit through the contact 124' with each operation of a typewriter key. The circuit to the unlocking coil extends from the power line 360 through the contacts 124' and 128', switch arm 130, conductors 362 and 372, switch arm 130, contacts 128 and 126, and conductor 380 to the coil 304 which is grounded through conductors 378 and 366.

In order to permit the switches 120, 160 and 340 to carry substantial currents without sparking, a capacitor 386 is connected in parallel with these switches.

The preferred embodiment of the invention has been illustrated and described, but changes and modifications can be made and some features can be used in different combinations without departing from the invention as defined in the claims.

What is claimed is:

1. In a typewriter, ribbon spool holders at opposite sides of the typewriter, mechanism for rotating each of the spool holders, driving means, motion-transmitting connections between the driving means and said mechanisms, the motion-transmitting connections including a shaft movable axially through a stroke and operably connected with the mechanism for rotating different ones of the spool holders when at different ends of its stroke to transmit power to one or the other of the mechanisms for rotating the spool holders, cam means for moving the shaft axially including two cams, each of which is located toward an opposite end of the shaft and each of which has a cam surface on an annular side surface thereof, the cam surfaces of the cams facing each other axially on the shaft, a lever having a fulcrum at a mid portion thereof between the cams and about which the lever rocks selectively into two different positions, and abutment surfaces at opposite ends of the lever constituting part of the cam means, the lever when rocked to one of said positions having the abutment surface at one end in the path of one cam surface and its abutment surface at the other end beyond the periphery of the other cam, and the lever when rocked to the other of said positions having its abutment surfaces reversed as to said cams, and actuating means operated from the spool holders for rocking the lever on its fulcrum between said different positions, said actuating means including elements rotatable with the spool holders.

2. The typewriter described in claim 1 characterized by the elements rotatable with the spool holders being carried by ribbon spools on the holders and being movable into inoperative positions and held in inoperative positions by ribbons wrapped on the spools, and yielding means for moving said elements into operative position whereby said elements move automatically into operative position when the ribbon is unwrapped from each spool.

3. The typewriter described in claim 1 characterized by the lever having its fulcrum at a location substantially midway between the ends of said lever, and supported from the typewriter, the abutment surfaces, of the cam means being end faces of the lever.

4. A multi-ribbon typewriter including a carriage having a platen that rotates about its longitudinal axis, ribbon spool holders near opposite ends of the platen, guide means along which ribbons from a spool on the holder at one end of the platen pass to the front of the platen and lengthwise thereof and then to a spool on the spool holder at the other end of the platen, driving means for selectively driving either spool holder in a direction to wrap the ribbons fed from a spool on the other holder, a lock for each holder operable to prevent unwinding of the ribbons from a spool on that holder, a carriage escapement control bar, means for turning the platen, means responsive to the turning of the platen for engaging the locks, and release means for the locks, actuating mechanism for said release means, said actuating means being operated from the carriage escapement control bar.

5. The typewriter described in claim 4 characterized by the lock for each spool holder including a toothed wheel connected with the spool holder, the wheels being correlated with their spool holders so as to turn in opposite directions as their spool holders turn in, and a pawl adjacent to each wheel in position to engage teeth on that toothed wheel.

6. The typewriter described in claim 5 and characterized by the driving means for the spool holders including gears that are shifted into different positions to reverse the direction of the drive of the ribbons, and the toothed wheels that are engaged by the pawls being gears of the driving means.

7. The typewriter described in claim 6 characterized by a gear of the driving means being connected directly to each of the spool holders, an electrically operated motor that operates intermittently, and motion-transmitting connections between the motor and the gears connected directly to the spool holders, said motion-transmitting connections including the gears that shift positions to reverse the direction of drive, and the pawls engaging teeth on the gears that are connected directly to the spool holders.

8. The typewriter described in claim 4 characterized by said means for operating the locks being electric, and controls for said electrical means for operating the locks including a switch and cam means connected to the platen for operating the switch.

9. The typewriter described in claim 8 characterized by the electrically operated means for actuating the locks including also means for releasing the locks, and the controls for said electrically operated means including another switch actuated by the carriage escapement control bar.

10. Ribbon feed control means for a typewriter of the class in which there is a platen in front of which paper is located, a ribbon is located in front of the paper in position to be struck by a type block that is moved into and out of impression-producing position with respect to the ribbon, paper and platen in response to the operation of a key of the typewriter, including in combination ribbon spool holders for rotating spools on which a typewriter ribbon is wound, an electric actuator that turns one of the spool holders with a step-by-step movement, a switch for supplying impulses of power to the actuator, a motion-transmitting connection between the switch and a part of the typewriter that moves with every operation of the typewriter key, and ratchet means in the motiontransmitting connection for operating the switch when the key is moving in one direction only, the ratchet means including a pawl that reciprocates with the motion-transmitting means and an actuator on the switch across which the pawl ratchets when moving in one direction, the actuator being displaced by the pawl to operate the switch when moving in the opposite direction to rotate the spool holder during a portion of the key operation when a type block associated with the key is out of its impressionproducing position.

11. Ribbon feed control means for a typewriter of the class having keys for different letters, said control means including ribbon spool holders on which the typewriter ribbon is wound, mechanism for rotating the spool holders including a gear associated with each of the spool holders, the gears being rotatable in opposite directions while the ribbon feeds from a spool on one holder to another spool on the other holder, locking means for selectively preventing rotation of the gears including separate pawls that engage between teeth of the respective gears, and cam means having resilient motion-transmitting connections that press the pawls into engagement with the teeth of the said gears.

12. The ribbon feed control means described in claim 11 characterized by an actuator for turning one of the gears and its ribbon spool holder while the other gear and ribbon spool holder is locked against rotation by its pawl whereby tension is imparted to the ribbon.

13. The ribbon feed control means described in claim 12 characterized by another actuator which operates the cam means to retract the pawls from engagement with the gears, and the other actuator including a part controlled from a portion of the typewriter which moves whenever a key of the typewriter is operated.

14. In a typewriter of the class having keys for striking letters and at least one ribbon that is struck by letters operated by said keys, the combination with said ribbon of ribbon feed means including a stepping motor, means for locking the ribbon feed at one end while the stepping motor operates the feed means to tension the ribbon, and means responsive to the operation of a key to unlock said means for locking the ribbon feed, the stepping motor being a reciprocating electric motor that moves in response to successive impulses of electric current, and the locking and unlocking means including electro-magnetic coils.

15. The typewriter described in claim 14 characterized by switches for controlling the supply of electricity to the electromagnetic coils, said switches including a locking switch responsive to turning of the platen and constituting a part of the means for locking the ribbon feed, and an unlocking switch constituting part of the means responsive to the operation of a key.

16. In a typewriter of the class that has parts which move with respect to one another during routine operation of the typewriter, the combination including a ribbon feed, an electric stepping motor that operates the ribbon feed, a first electric switch for supplying successive impulses of power to the motor to operate it for successive steps, means responsive to the movement of one part of the typewriter for momentarily closing said first electric switch, a second switch responsive to an impulse produced by the closing of the first switch, a circuit that includes the first switch in parallel with the second switch and through which the second switch supplies impulses to the stepping motor, and means for controlling the duration of the time that the second switch remains closed for insuring ample power for the stepping motor, the

operation of the control means being independent of the speed of operation of said means which are responsive to the movement of said one part of the typewriter.

17. The typewriter described in claim 16 characterized by a ribbon spool from which the ribbon unwinds, and another ribbon spool on which the ribbon winds, locking means that stop the unwinding spool while the stepping motor continues to turn the winding spool and thereby impart tension to the ribbon, a platen, and a third switch operated by movement of the platen to supply energy to operate the locking means, a circuit containing said third switch and that connects with the second switch to supply power to operate the second switch.

18. A multi-ribbon typewriter device including a plurality of ribbon guides for holding superimposed ribbons in front of a platen of a typewriter, hinge connections on which each of the ribbon guides swings about an axis and between a working position and an elevated inoperative position, the inoperative position being one which permits the insertion of new sheets of paper into the typewriter, the axis of the hinge connections of all of the ribbon guides being substantially coincident, latch means that hold the ribbon guides in elevated positions, a rotatable element that moves the latch means with reciprocating movement, said latch means having guide-engaging surfaces on opposite sides thereof and operating to release a different guide upon each direction of movement of said reciprocating movement.

19. The multi-ribbon typewriter described in claim 18 characterized by there being slots in the guides for receiving a part of the latch means, the slots being in alignment in the direction of extent of the movement of the carriage of the typewriter, but successive slots being offset for a portion of their length, the latch means including an armthat extends through the slots of all of the ribbon guides when said ribbon guides are in elevated position, the arm having shoulders on opposite sides thereof constituting the guide-engaging surfaces.

20. The multi-ribbon typewriter device described in claim 19 characterized by the distance across the arm including both shoulders being somewhat greater than the overlapping portions of the slots in the direction in which the slots are offset from one another, and the offsets of successive slots being at opposite ends of the slots whereby oscillating movement of the arm releases a successive guide with each oscillating stroke of the arm.

References Cited UNITED STATES PATENTS 827,942 8/1916 Sanderson 197-162 1,084,656 1/1914 Myers 197-160 1,704,020 3/1929 Sacerdote 197-153 2,069,277 2/1937 Sacerdote 197-153 2,126,323 8/1938 Handley 197-153 2,128,267 8/1938 Sacerdote 197-153 2,407,799 9/1946 Ritzert 197-153 X 2,742,132 4/1956 Anderson 197-160 2,869,704 1/1959 Gates 197-151 2,978,089 4/1961 Dodge et a1 197-161 2,930,470 3/1960 Roller et al 197-151 ROBERT E. PULFREY, Primary Examiner.

ERNEST T. WRIGHT, Examiner. 

1. IN A TYPEWRITER, RIBBON SPOOL HOLDERS AT OPPOSITE SIDES OF THE TYPEWRITER, MECHANISM FOR ROTATING EACH OF THE SPOOL HOLDERS, DRIVING MEANS, MOTION-TRANSMITTING CONNECTIONS BETWEEN THE DRIVING MEANS AND SAID MECHANISMS, THE MOTION-TRANSMITTING CONNECTIONS INCLUDING A SHAFT MOVABLE AXIALLY THROUGH A STROKE AND OPERABLY CONNECTED WITH THE MECHANISM FOR ROTATING DIFFERENT ONES OF THE SPOOL HOLDERS WHEN AT DIFFERENT ENDS OF ITS STROKE TO TRANSMIT POWER TO ONE OR THE OTHER OF THE MECHANISMS FOR ROTATING THE SPOOL HOLDERS, CAM MEANS FOR MOVING THE SHAFT AXIALLY INCLUDING TWO CAMS, EACH OF WHICH IS LOCATED TOWARD AN OPPOSITE END OF THE SHAFT AND EACH OF WHICH HAS A CAM SURFACE ON AN ANNULAR SIDE SURFACE THEREOF, THE CAM SURFACES OF THE CAMS FACING EACH OTHER AXIALLY ON THE SHAFT, A LEVER HAVING A FULCRUM AT A MID PORTION THEREOF BETWEEN THE CAMS AND ABOUT WHICH THE LEVER ROCKS SELECTIVELY INTO TWO DIFFERENT POSITIONS, AND ABUTMENT SURFACES AT OPPOSITE ENDS OF THE LEVER CONSTITUTING PART OF THE CAM MEANS, THE LEVER WHEN ROCKED TO ONE OF SAID POSITIONS HAVING THE ABUTMENT SURFACE AT ONE END IN THE PATH OF ONE CAM SURFACE AND ITS ABUTMENT SURFACE AT THE OTHER END BEYOND THE PERIPHERY OF THE OTHER CAM, AND THE LEVER WHEN ROCKED TO THE OTHER OF SAID POSITIONS HAVING ITS ABUTMENT SURFACES REVERSED AS TO SAID CAMS, AND ACTUATING MEANS OPERATED FROM THE SPOOL HOLDERS FOR ROCKING THE LEVER ON ITS FULCRUM BETWEEN SAID DIFFERENT POSITIONS, SAID ACTUATING MEANS INCLUDING ELEMENTS ROTATABLE WITH THE SPOOL HOLDERS. 